Trim zucchini ends, halve lengthwise, and cut into ¼" slices. Mince garlic. Stem and mince parsley. Pat chicken breasts dry, and season both sides with ¼ tsp. salt and a pinch of pepper.
Roast the Vegetables
In a mixing bowl, combine ricotta, half the Parmesan (reserve remaining for vegetables), half the parsley (reserve remaining for garnish), truffle oil, 1 tsp. olive oil, and a pinch of salt and pepper.
Sear the Chicken
Place a medium oven-safe pan over medium-high heat and add 1 tsp. olive oil. Add chicken to hot pan and Sear until well-browned on both sides, 3-5 minutes per side. Transfer chicken to a plate. Reserve pan; no need to wipe clean.
Make the Sauce
Return pan used to sear chicken to medium heat. Add remaining garlic and cook until aromatic, 30-60 seconds. Stir in marinara, 2 Tbsp. water, and red pepper flakes (to taste). Bring to a simmer and remove from burner.
Finish the Chicken
Place zucchini on prepared baking sheet and toss with half the garlic (reserve remaining for sauce), 2 tsp. olive oil, ¼ tsp. salt, and a pinch of pepper. Spread into a single layer and top with remaining Parmesan. Roast until tender, 16-18 minutes. Return chicken and any accumulated juices to pan with sauce and flip to cover chicken. Top chicken with ricotta mixture. Place pan in oven and cook until chicken reaches a minimum internal temperature of 165 degrees, 12-15 minutes.
Finish the Dish
Spoon sauce on a plate. Serve chicken on sauce and vegetables alongside. Garnish with remaining parsley.